The Science of Sharp: Decoding Japanese Steel
In the world of professional cutlery, “Japanese Steel” isn’t just a label—it’s a gold standard. But if you’ve ever shopped for a high-end knife, you’ve likely been bombarded with terms like VG-10, Damascus, HRC, and High-Carbon.
At Kyoku Japanese knives, we believe that a master of the kitchen should understand their tools as well as a Samurai understood his sword. Today, we’re stripping away the mystery and decoding the metallurgy that makes our blades world-class.
The Heart of the Blade: VG-10 Steel
If you’re looking for the “sweet spot” of Japanese steel, look no further than VG-10. Often called “Gold Steel” (the ‘G’ stands for Gold), it is a high-carbon stainless steel produced in Japan that has become the darling of the culinary world.
Why we use it at Kyoku:
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Edge Retention: Thanks to its high carbon content, VG-10 can be sharpened to a razor edge and—more importantly—it stays that way through hundreds of onions.
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Corrosion Resistance: Unlike traditional carbon steel which can rust if you look at it wrong, the added Chromium in VG-10 makes it remarkably resistant to stains and rust.
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The “Vanadium” Secret: The ‘V’ in VG-10 stands for Vanadium. This element makes the steel finer-grained and tougher, allowing us to grind the blade to a staggering 13–15 degree angle.
The Art of the Layer: What is Damascus Steel?
One of the most common misconceptions in the kitchen is that “Damascus” is a type of steel. In reality, modern Damascus is a forging technique.
When you see those beautiful, swirling water-like patterns on a Kyoku blade, you are looking at pattern-welding. We take a core of high-performance steel (like VG-10) and laminate it between multiple layers of softer, more flexible stainless steel.
The benefits of the Damascus cladding:
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Protection: The softer outer layers act as a “shock absorber” for the hard, brittle core.
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Food Release: The microscopic irregularities in the surface patterns help reduce suction, allowing the blade to glide through sticky vegetables.
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Aesthetic Legacy: It honors the ancient swordsmiths who folded steel to remove impurities, creating a unique “fingerprint” on every knife.
Understanding the Numbers: Rockwell Hardness (HRC)
You’ll often see a number like 58-62 HRC on our product pages. This refers to the Rockwell Scale, which measures how hard the steel is.
| Steel Type | Typical HRC | Characteristics |
| Western Steel | 54–56 | Softer, tougher, but dulls quickly. Requires frequent honing. |
| Kyoku VG-10 | 60–62 | Very hard. Exceptional sharpness and edge life. |
| High-Carbon Specialty | 63+ | Extremely sharp but very brittle; prone to chipping if mishandled. |
A higher HRC means the knife can be thinner and sharper, but it requires a more disciplined hand. At Kyoku, we aim for that 60+ HRC “sweet spot”—maximum sharpness without becoming too fragile for everyday use.
Beyond VG-10: Other Steels in the Arsenal
While VG-10 is our flagship, we also utilize other specialized steels to suit different needs:
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AUS-10: A close cousin to VG-10. It’s slightly tougher and easier to sharpen, making it a favorite for those who want high performance with a bit more durability.
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440C High-Carbon: Used in our more entry-level series, this steel provides a fantastic balance of stain resistance and hardness for the aspiring home cook.
Why Does This Matter for Your Creativity?
At the end of the day, metallurgy is just a means to an end. A thinner, harder blade means you don’t have to “saw” through a tomato; you simply let the weight of the knife do the work. It means your herbs stay green because you’ve sliced them cleanly rather than crushing them.
By choosing the right steel, you aren’t just buying a kitchen tool—you’re investing in a piece of engineered art that respects your ingredients.
